Collectindust240Z Posted February 24, 2006 Share Posted February 24, 2006 Hey all. I've been trying to get the heap running for a while now, to get it on the road before I decide it's fate. It just has a nasty stumble right off idle. I'm not really sure where my timing is since I don't think I have the right pointer (I'm using the euro damper on a F54). I know that sounds retarded, but it's the truth. I sorta timed it by ear. It sounds like it wants more timing, but the dizzy is maxed out. Okay before I sound like a total moron, here's the lowdown. '82 F54 flat top bottom end-stock, P90 head shaved .070 (I know it should be .080, but the machine shop could only come up with .070 shims), schneider 480/274 cam installed straight up, 280ZX dizzy, Crane HI6 w/ PS92 coil, Dellorto 40's, Motorsport 6 into 2 header, no exhaust now, just a supertrap on collector. Any ideas? Carbs are synced, float levels look good, fuel pressure at 4.5 psi. It runs rich as all get out. Idles OK, rips past 2500, anything in between is crap, pops through carbs, out exhaust. NOT MUCH FUN! Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 24, 2006 Share Posted February 24, 2006 I don't know much about the L6, but in a GMv8 if the dizzy timing was maxed and it was stumbling I'd suspect a timing issue. Did ya have the dizzy out? If so did you install it properly? Maybe a tooth off? I hate it when that happens. Quote Link to comment Share on other sites More sharing options...
technicalninja Posted February 24, 2006 Share Posted February 24, 2006 Real important to verify timing. Make piston stop from sparkplug with bolt in it. Carefully find interferance point close to TDC. Make simple adjustable pointer. mark balancer with crayon/liquid paper. rotate balancer in opposite dir until you once again just barely hit stop. mark balancer again. difference between marks is TDC for that pointer set up. Balance could be marked in center position with notch or model paint. Better to move pointer around untill original factory mark can be used. "test pointer" can be made out of coathanger and car will be able to be timed from it. Use an "advance" timing light to set timing. Real good idea to check factory set up anyways as I have seen completely stock set ups 4 degrees off. This method can be used to mark TDC at any position for custom setups. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 24, 2006 Share Posted February 24, 2006 Sounds like you know what's up. I ran my timing retarded to pass smog when I first got my Z. Same thing. Dead below 2500, then the mech advance kicked in and the thing took off. Thing is, it was actually still slow, but it felt so much better that it felt like it went like a bat outta hell. Get a timing light on it. If you can't get any more timing, then you'll have to pull the distributor shaft and rotate it one tooth. You should be running about 15-20 degrees at idle, or somewhere in the 32 to 38 degrees total advance range. Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted March 2, 2006 Author Share Posted March 2, 2006 In regards to my last post about my real bad stumble. I figured it out. And I feel really stupid. I made some wood carb spacers. It's an old hot rodder trick that I thought would work for me. Only I never sealed the wood. I used maple because the grain was nice and tight, and because it would smell good if it caught fire! Well...I have a nice vacuum leak right behind the carbs. That would explain my problems. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted March 2, 2006 Share Posted March 2, 2006 I merged the two posts. Not necessary to start a whole new post to conclude this one. Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted March 2, 2006 Author Share Posted March 2, 2006 sorry Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.